Compound monograph
Semaglutide
Also known as: Ozempic, Wegovy, Rybelsus
§1 Definition
Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist, an injectable or oral peptide analog that mimics endogenous GLP-1 to stimulate insulin secretion, suppress glucagon, and slow gastric emptying. It is FDA-approved as Ozempic and Rybelsus for type 2 diabetes and as Wegovy for chronic weight management, and is also approved to reduce major cardiovascular events in adults with cardiovascular disease and obesity or overweight.
Educational purposes only, not medical advice. Dosing figures below are documented ranges from cited literature, not a recommendation for any individual. Consult a qualified provider before administering anything.
§2 Evidence tier and regulatory status
Evidence tier
1 — FDA-approved
Approved by the FDA for at least one indication, backed by multiple randomized controlled trials.
FDA-approved. Ozempic (injectable) approved December 5, 2017 for glycemic control in type 2 diabetes. Rybelsus (oral tablet) approved September 20, 2019, also for type 2 diabetes. Wegovy (injectable) approved June 4, 2021 for chronic weight management; its label was expanded in March 2024 to include reducing the risk of major adverse cardiovascular events in adults with established cardiovascular disease and obesity or overweight.
§3 Documented dosing
| Context | Range | Frequency | Source |
|---|---|---|---|
| Type 2 diabetes glycemic control (Ozempic) | 0.25–2 mg | once weekly, titrated upward over 8+ weeks; maintenance up to 2mg/week | [1] |
| Chronic weight management, adults (Wegovy) | 0.25–2.4 mg | once weekly, 16-17 week titration to a 2.4mg maintenance dose (1.7mg as an alternate maintenance dose if 2.4mg isn't tolerated) | [3] |
| Chronic weight management, pediatric 12+ (Wegovy) | 0.25–2.4 mg | once weekly, same titration schedule; maintenance fixed at 2.4mg only | [3] |
§4 Reconstitution math
FDA-approved semaglutide (Ozempic, Wegovy) is supplied as a ready-to-use liquid solution in prefilled pens or single-dose prefilled syringes — it is not a lyophilized powder requiring reconstitution. Rybelsus is an oral tablet. Compounded or research-grade semaglutide sold as a lyophilized vial is not FDA-regulated, and no published primary-source reconstitution protocol exists for it; the vial sizes below reflect what is commonly sold by compounding sources, not an FDA-documented figure.
| Vial | Water | Concentration | Draw volume | Units (U-100) |
|---|---|---|---|---|
| 2 mg | 2.0 mL | 1000 mcg/mL | 0.25 mL | 25.0 |
| 5 mg | 2.0 mL | 2500 mcg/mL | 0.1 mL | 10.0 |
| 10 mg | 2.0 mL | 5000 mcg/mL | 0.05 mL | 5.0 |
- Concentration
- 1000 mcg/mL
- Draw volume
- 0.25 mL
- Syringe units
- 25.0
- Doses per vial
- 8
§5 What the research shows
| Trial | Phase | n | Duration | Endpoint | Result | Source |
|---|---|---|---|---|---|---|
| STEP 1 | Phase 3 | 1961 | 68 weeks | Percent body weight change and proportion achieving ≥5% weight loss, in adults with obesity or overweight without diabetes | -14.9% mean body weight change with semaglutide 2.4mg vs -2.4% with placebo; 86.4% of the semaglutide group achieved ≥5% weight loss vs 31.5% with placebo. | [7] |
| SUSTAIN-6 | Phase 3b | 3297 | 104 weeks | Composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke, in adults with type 2 diabetes at high cardiovascular risk | 6.6% of the semaglutide group (0.5mg or 1.0mg) reached the composite endpoint vs 8.9% with placebo (hazard ratio 0.74, 95% CI 0.58-0.95). | [8] |
| SELECT | Phase 3 | 17604 | mean follow-up 39.8 months | Composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke, in adults with established cardiovascular disease and obesity or overweight without diabetes | 6.5% of the semaglutide 2.4mg group reached the composite endpoint vs 8.0% with placebo (hazard ratio 0.80, 95% CI 0.72-0.90); mean weight loss was 9.4%. | [9] |
§6 Safety and reported adverse effects
| Effect | Incidence | Source |
|---|---|---|
| Nausea (Ozempic, 0.5mg/1mg doses) | 15.8% / 20.3% vs 6.1% placebo | [1] |
| Nausea (Wegovy, 2.4mg) | 44% vs 16% placebo | [3] |
| Vomiting (Wegovy, 2.4mg) | 24% vs 6% placebo | [3] |
| Diarrhea (Wegovy, 2.4mg) | 30% vs 16% placebo | [3] |
| Constipation (Wegovy, 2.4mg) | 24% vs 11% placebo | [3] |
| Abdominal pain (Wegovy, 2.4mg) | 20% vs 10% placebo | [3] |
| Thyroid C-cell tumors | — | [1], [3] |
Thyroid C-cell tumor risk is based on rodent studies; the FDA label states human relevance is unknown, and no human incidence rate has been published for this risk — it is listed above without an incidence figure because none exists, not because it was omitted.
Contraindications
- Personal or family history of medullary thyroid carcinoma (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- Known hypersensitivity to semaglutide or any product excipient
Known interactions
- Increased hypoglycemia risk when combined with insulin or insulin secretagogues (e.g. sulfonylureas) — a dose reduction of those agents may be needed.
- Delays gastric emptying, which can theoretically affect absorption of concomitant oral medications, though labeled clinical studies found no clinically relevant interaction with metformin, warfarin, digoxin, atorvastatin, or oral contraceptives specifically tested.
§7 Storage and handling
- Lyophilized
- The FDA-approved product is not lyophilized (see reconstitution notes above). No FDA-published storage data exists for compounded lyophilized semaglutide vials.
- Reconstituted
- Per manufacturer patient labeling, unopened pens are refrigerated at 2-8°C (36-46°F) until first use. Reported in-use storage duration varies by presentation and source; this research pass could not independently confirm a single exact figure from the FDA label's storage section, so consult the specific product's patient information insert for the authoritative duration rather than relying on this page alone.
§8 Sourcing considerations
- Confirm the product is the FDA-approved pen or tablet, not an unregulated compounded or "research use only" powder claiming to be semaglutide.
- For any compounded version, ask for a Certificate of Analysis from an independent, named third-party lab, not the seller's own in-house testing.
- Confirm cold-chain shipping and handling were maintained, given the product's refrigeration requirements.
- Understand that compounded semaglutide is not FDA-approved and its purity and potency are not FDA-verified.
§9 FAQ
What is semaglutide used for?
Glycemic control in type 2 diabetes (as Ozempic or Rybelsus), chronic weight management (as Wegovy), and reducing cardiovascular event risk in adults with established cardiovascular disease plus obesity or overweight (Wegovy) or type 2 diabetes at high cardiovascular risk (Ozempic, per SUSTAIN-6).
Is Ozempic the same as Wegovy?
Same active ingredient and molecule, but different FDA-approved dose ranges and indications: Ozempic is approved up to 2mg weekly for type 2 diabetes, while Wegovy is approved up to 2.4mg weekly for chronic weight management.
How long does semaglutide stay in your system?
About 5 weeks after the last dose, based on its roughly 1-week elimination half-life.
What is the semaglutide starting dose?
0.25mg once weekly, for both the Ozempic and Wegovy titration schedules, before increasing over several weeks.
Does semaglutide need to be refrigerated?
Yes, before first use. See the storage section above for the caveat on post-first-use duration, which this page could not fully verify against the FDA label in this research pass.
What are the most common semaglutide side effects?
Gastrointestinal effects — nausea, diarrhea, vomiting, and constipation — are the most commonly reported. See the adverse effects table above for trial-reported incidence rates.
Can semaglutide cause thyroid cancer?
Unknown in humans. It is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2 because of thyroid C-cell tumors observed in rodent studies; human relevance has not been established.
Does semaglutide reduce heart attack and stroke risk?
Yes, in the populations studied: SUSTAIN-6 (type 2 diabetes, high cardiovascular risk) and SELECT (established cardiovascular disease, obesity or overweight, without diabetes) both showed a reduced rate of the composite cardiovascular endpoint versus placebo.
§10 Sources
- [1] Ozempic (semaglutide) injection — Highlights of Prescribing Information. U.S. Food and Drug Administration, 2023. FDA. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/209637s020s021lbl.pdf
- [2] OZEMPIC- semaglutide injection, solution. DailyMed, National Library of Medicine (NIH), 2023. FDA. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=adec4fd2-6858-4c99-91d4-531f5f2a2d79
- [3] WEGOVY (semaglutide) injection — Highlights of Prescribing Information. U.S. Food and Drug Administration, 2024. FDA. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/215256s021lbl.pdf
- [4] WEGOVY- semaglutide injection, solution. DailyMed, National Library of Medicine (NIH), 2024. FDA. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f5e548d0-cc79-4c34-a3f5-e20a5b8b6564
- [5] RYBELSUS (semaglutide) tablets — approval record. U.S. Food and Drug Administration, 2019. FDA. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2019/213051Orig1s000ChemR.pdf
- [6] Semaglutide, CID 56843331. PubChem, National Library of Medicine (NIH), 2026. Other. https://pubchem.ncbi.nlm.nih.gov/compound/Semaglutide
- [7] Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). New England Journal of Medicine, 2021. Peer-reviewed. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183
- [8] Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). New England Journal of Medicine, 2016. Peer-reviewed. https://www.nejm.org/doi/full/10.1056/NEJMoa1607141
- [9] Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT). New England Journal of Medicine, 2023. Peer-reviewed. https://www.nejm.org/doi/full/10.1056/NEJMoa2307563